Thursday, around 10 p.m.: Robbery takes place at at 7/11 convenience store in Cambridge, near the MIT campus.

Thursday, 10:20 p.m.: An MIT campus police officer was found shot in his vehicle in the area of Vassar and Main Streets. According to authorities, the officer was found with multiple gunshot wounds. He was transported to Massachusetts General Hospital and pronounced dead.

Moments later, police received reports of an armed carjacking by two males in the area of Third Street in Cambridge. The victim was carjacked at gunpoint by two males and was kept in the car with the suspects for approximately a half hour. The victim was released at a gas station on Memorial Drive in Cambridge. He was not injured.

Authorities say the suspects threw explosives from the car as police followed it into Watertown. The suspects and police exchanged gunfire, and one of the suspects was critically injured.

Friday, 1:45 a.m.: Suspect #1 was pronounced dead. He was the man seen in the black hat and considered a suspect in the Boston Marathon bombings.

Friday, 2 a.m.: The FBI releases a new photo of Suspect #1 and Suspect #2 on its website.

Friday, 4 a.m.: Boston Police and Cambridge Police Chief confirm the two men involved in the fatal shooting of an MIT campus police officer, and a shootout/chase into Watertown were the same suspects believed to be involved in the Boston Marathon bombings.

The Middlesex County D.A. confirms Suspect #1 has died while Suspect #2 escaped.

Friday, 4 a.m.: Police release a new image of Suspect #2, from a 7/11 convenience store that was robbed several hours earlier.

Friday, 5:30 a.m.: Gov. Patrick suspends all public transit service on the MBTA system.

People living in a number of communities ordered to stay inside homes. The communities included Watertown, Waltham, Belmont, Newton, Allston-Brighton and Cambridge.

MIT, Harvard and other local colleges cancel classes.

Friday, 6:45 a.m.: The Associated Press reports that the men are from a Russia region near Chechnya and have lived in the U.S. for at least one year. The AP identified the surviving suspect as Dzhokhar A. Tsarnaev, 19, of Cambridge, Mass.